The American College of Sports Medicine and the American Heart Association released an updated version of the national guidelines for physical fitness. The guidelines define the minimum physical activity required to maintain good health, and have been updated to allow for flexibility and make it easier to determine how much fitness is enough for you.
The expert panel (which was made up of physicians, epidemiologists, exercise scientists and public health specialists) that developed the guidelines recommends that all healthy adults need aerobic physical activity that is moderate-intensity (such as brisk walking) for at least 30 minutes five days a week, or that is vigorous-intensity (such as jogging) for at least 20 minutes three days a week. Also recommended are twice weekly muscular strength building and endurance activities. As these are weekly minimums, the report points out that to lose weight or improve your personal fitness, more exercise should be completed.
The report expands on activity levels needed to lose or gain weight, and also on the benefits and risks of exercise. It also includes variations and combinations of moderate- and vigorous-intensity workouts.